Author, Donkey, Bureaucrats, Administrators
53,803
edits
Changes
Jump to navigation
Jump to search
no edit summary
{{OpenPagesTop}}
{{Taxobox
|kingdom =
|sub-kingdom =
|phylum =[[:Category:Arthropods|Arthropoda]]
|super-class =
|class =[[:Category:Insecta|Insecta]]
|sub-class =
|super-order =
|order =
|sub-order =
|super-family =
|family =Ceratopogonidae
|sub-family =
|genus =Culicoides
|species =
}}
Also known as: '''''Midges'''''<br>
The most important veterinary species is '''''Culicoides''''' <br>
==Introduction==
==Introduction==
This parasite is found worldwide and attacks humans and a wide variety of animals. The only genus of the family ''Ceratopogonidae'' of current veterinary significance is ''Culicoides''.
The midge is a vector for several viruses, including [[Bluetongue Virus|Bluetongue]] and [[African Horse Sickness|African horse sickness]].
It causes allergic dermatitis of horses, primarily affecting the base of the tail and the withers, and induces an intermediate-type hypersensitivity reaction to the midge saliva, known as [[Culicoides Hypersensitivity|'Sweet itch']]
==Identification==
Culicoides are small flies 2-5mm long with a dark colouring, more commonly known as '''biting midges'''. They have a characteristic arched thorax giving a 'hump-backed' appearance. The wings are mottled.
'''Recognition'''
==Life cycle==
Eggs are laid onto plants near water and the larvae fall into water and pupate. The life cycle takes '''6-12 months''' to complete in temperate climates, but can take only '''1 month''' in tropical climates. Females of most species are adapted to sucking blood from the host.
''Culicoides'' take blood meals from vertebrate hosts and breed in damp, dung-enriched soil, and so are abundant in the vicinity of domestic livestock. Once eggs are laid in the soil, ''Culicoides'' larvae progress through four stages and pupate before becoming an adult midge. The lifecycle is greatly influenced by temperature: in temperate regions such as Britain, the adult midge population declines in October and is absent by December. The fourth larval stage overwinters, and adults re-appear the following April. The environmental conditions also affect the activity of midges in several ways. ''Culicoides'' survive around 10 days in warm weather but up to one month when conditions are cooler and are most active at night, from an hour before sunset to an hour after sunrise. Activity is decreased by windy conditions, and increased during the day when the weather is dull.
'''Life cycle'''
==Distribution==
The ''Culicoides'' species found in the British Isles are ''C. pulicaris'' and ''C. obsoletus'', which are also common across central and northern Europe. Knowledge of the distribution of these species in the UK is incomplete but the insects tend to gather where breeding sites and hosts occur in tandem, with the highest midge concentrations in areas containing cattle, horses and pigs. Removal of livestock decreases populations of ''Culicoides'' by a factor of 10 to 20<sup>1</sup>, but some persist by feeding on wild animals and man. Hill sites have fewer midges as climatic conditions are less favourable, and the presence of sheep encourages the midge population less than that of cattle.
In Britain, studies are ongoing to determine midge distribution, seasonal incidence and the competency of the various ''Culicoides'' species to act as BTV vectors.
'''Pathogenesis'''
Classically, the major vector for [[Bluetongue Virus|BTV]] is ''Culicoides imicola''. This midge is found throughout Africa, the
Middle East, southern Asia, Portugal, Greece, Corsica, Sardinia, Sicily and areas of Italy<sup>1</sup>, and its distribution appears to be extending northwards. However, ''C. imicola'' has not yet been demonstrated in the United Kingdom.
{{Learning
|literature search = [http://www.cabdirect.org/search.html?rowId=1&options1=AND&q1=%28%28%28od%3A%28Ceratopogonidae%29+OR+od%3A%28midges%29%29+AND+sc%3A%22ve%22%29%29+OR+%28%28%28title%3A%28Ceratopogonidae%29+OR+title%3A%28midges%29%29++AND+sc%3A%22ve%22%29%29&occuring1=freetext&rowId=2&options2=AND&q2=&occuring2=freetext&rowId=3&options3=AND&q3=&occuring3=freetext&publishedstart=2000&publishedend=yyyy&calendarInput=yyyy-mm-dd&la=any&it=any&show=all&x=52&y=12 Ceratopogonidae publications since 2000]
}}
==References==
#DEFRA (2002) [http://www.defra.gov.uk/foodfarm/farmanimal/diseases/atoz/documents/bluetongue_technical.PDF Technical Review - Bluetongue : The Virus, Hosts and Vectors.]
{{review}}
{{OpenPages}}
[[Category:Biting_Flies]]
[[Category:Biting_Flies]]
[[Category:Expert_Review]]